This proposal describes a 5-year training program for completing the graduate program in Immunology at Stanford University. The principal investigator is an MD/PhD student, who has completed the first two years of medical school and is beginning his graduate studies. Stanford University combines strengths in both basic science and clinical research, especially as it pertains to the molecular basis of immunology, and thus will be fertile environment for developing my career in academic medicine. My proposal focuses on molecular aspects of macrophage activation, especially as it relates to signaling by nuclear hormone receptors, PPAR gamma and delta. Previous studies by various laboratories have identified these transcription factors as key regulators of macrophage lipid metabolism, inflammatory response and atherosclerosis. However, the molecular programs by which these receptors control macrophage biology and activation remain poorly understood. The studies proposed in the present grant application will take biochemical, molecular, and genetic approaches to further investigate how PPAR gamma and delta orchestrate the macrophage response to incoming fatty acids.